Respiratory Syncytial Virus: A Narrative Review of Updates and Recent Advances in Epidemiology, Pathogenesis, Diagnosis, Management and Prevention.

Respiratory syncytial virus (RSV) continues as the major cause of acute lower respiratory tract infections in children around the world, and its substantial morbidity, particularly among infants and high-risk children, poses a significant burden on healthcare systems worldwide. RSV infections occur as a spectrum, ranging from mild upper respiratory symptoms to severe bronchiolitis and pneumonia, and the number of infections shows seasonal variations in different latitudes, as well as lasting impacts, reflecting the COVID-19 pandemic. The pathogenesis of the virus involves epithelial cell invasion and/or fusion to form syncytia, along with exaggerated immune-mediated responses. Disease severity is known to depend on viral load, strain variation, and host immune immaturity. Severe RSV infection during infancy is notably linked with long-term respiratory sequelae such as recurrent wheezing and asthma. Diagnosis is based on clinical suspicion and laboratory confirmation using rapid antigen testing or nucleic acid amplification tests, namely PCR. Non-pharmaceutical interventions, maternal vaccination, and prophylaxis with monoclonal antibodies, e.g., palivizumab and nirsevimab, a newly introduced long-acting agent, are efficient protective and preventive measures. Treatment is still, for the most part, supportive in nature and focuses on oxygen supplementation, hydration, and respiratory support for patients with more severe disease courses; however, the development of immunoprophylaxis and vaccine candidates shows promise for reducing the global burden of RSV.